Multiframe video coding for improved performance over wireless channels /
The increasing popularity of mobile Personal Communication Systems in recent years has generated wide research and commercial interest in the development of video coders for videoconferencing on wireless channels. A widely used technique for video coding over wireless channels is the single frame b...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1998.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=737704021&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | The increasing popularity of mobile Personal Communication Systems in recent years has generated wide research and commercial interest in the development of video coders for videoconferencing on wireless channels. A widely used technique for video coding over wireless channels is the single frame block motion compensation (SF-BMC) approach which predicts blocks in the current frame of the video signal from those in the (single) previous frame. In this dissertation, we propose the use of multiple frames in block motion compensation as a more robust and bit-efficient procedure for coding and transmission of videoconferencing-type video signals over wireless channels. The multiframe BMC (MF-BMC) coder makes use of the redundancy that exists across multiple frames in typical videoconferencing sequences to achieve additional compression over that obtained by using the SF-BMC approach, such as in the base-level H.263 codec. The MF-BMC approach has an inherent ability of overcoming some transmission errors and is thus more robust when compared to the SF-BMC approach. We model the error propagation process in MF-BMC as a multiple Markov chain and analyze the probability that a block of video data is in error in the decoder. Based on the analysis, we conclude that the use of multiple frames in motion compensation decreases the block error probability in the decoder, thereby increasing robustness. We also use the Markov chain analysis to devise a simple scheme which randomizes the selection of the frame (amongst the multiple previous frames) used in BMC to achieve additional robustness. The MF-BMC coders proposed in this dissertation are a multiframe extension of the base-level H.263 coder. We compare the performances of the SF-BMC and the MF-BMC approaches over wireless channels by transmitting compressed video bitstreams over simulated slow-fading Rayleigh fading channel. The resulting peak signal-to-noise ratios (PSNR) of the reconstructed video in the receiver are used to quantitatively measure the improvement in error robustness. The reconstructed PSNR values for the MF-BMC approaches are found to be better than that for the SF-BMC approach. A similar improvement in PSNR for the MF-BMC approaches is also observed over additive white Gaussian noise channels. |
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| Item Description: | Vita. "Major Subject: Electrical Engineering". |
| Physical Description: | xii, 80 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references: pages 68-72. |